Income Taxes (Summary of Tax Provision Allocation to Financial Statement Items) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Abstract]
Income from operations	$ 31,406	$ 14,447	$ 14,759
Stockholders' equity, unrealized gain (loss) on investment securities & foreign currency	14	75	43
Total Income Tax Expense	$ 31,420	$ 14,522	$ 14,802